| 摘要 |
PURPOSE:To prevent generation of a jitter and an erroneous detecting of an index signal by providing an amplitude compensating circuit of both a discriminating pulse and a synchronizing pulse, in a discriminating pulse and synchronizing pulse fetching circuit, in a servo-signal processing circuit. CONSTITUTION:A servo-signal from a magnetic head 3 is amplified, passes through an LPF6, and is corrected to a prescribed level by an AGC7. An amplitude compensating circuit 9 fetches a discriminating pulse and a synchronizing pulse from an output signal of the AGC7 and compensates its amplitude. The circuit 9 is constituted of a differential amplifier 13 whose input impedance is high, a total reflection type delay line 14, a characteristic impedance terminal resistance 16 of the delay line, and reflected wave distribution reistances 19, 20. This circuit can compensate a time width of a waveform and an amplitude value by synthesizing an input signal waveform and a reflected waveform of the delay line, compensate the amplitude value of discriminating pulse and the synchronizing pulse, and can eliminate effectively a defect of the pulse. |
